diff --git a/tests/ipfwd/test_nhop_group.py b/tests/ipfwd/test_nhop_group.py
index a019762a85..dd8b8762e4 100644
--- a/tests/ipfwd/test_nhop_group.py
+++ b/tests/ipfwd/test_nhop_group.py
@@ -892,7 +892,14 @@ def test_nhop_group_interface_flap(duthosts, enum_rand_one_per_hwsku_frontend_ho
                                                             gather_facts['src_port'][i])
             logger.debug("No Shut fanout sw: %s, port: %s", fanout, fanout_port)
             fanout.no_shutdown(fanout_port)
-        time.sleep(20)
+        # todo: remove the extra sleep on chassis device after bgp suppress fib pending feature is enabled
+        # We observe flakiness failure on chassis devices
+        # Suspect it's because the route is not programmed into hardware
+        # Add external sleep to make sure route is in hardware
+        if duthost.get_facts().get("modular_chassis"):
+            time.sleep(180)
+        else:
+            time.sleep(20)
         duthost.shell("portstat -c")
         ptfadapter.dataplane.flush()
         testutils.send(ptfadapter, gather_facts['dst_port_ids'][0], pkt, pkt_count)